Engine cylinder head cover with integral breather apparatus, and engine incorporating same

Abstract

A breather apparatus for an internal combustion engine which, when casting a cylinder head cover, can improve the fluidity of molten metal and promote gas-liquid separation through effective use of an entire breather chamber. A breather apparatus for an internal combustion engine has a cylinder head cover in which a breather chamber is formed. In the breather chamber, a number of ribs extend from a side wall included in a peripheral wall of the chamber obliquely relative to a direction in which blowby gas flows in through inflow ports. The ribs extend up to where they are continuous with respective fixing bosses. The ribs include projecting lower edge portions which are partly cut out, forming respective concave portions.

1. A cylinder head cover for an internal combustion engine having a cylinder head, said cylinder head cover covering an upper portion of said cylinder head and having a breather apparatus formed therein,
 said breather apparatus comprising a part of the cylinder head cover which projects upwardly and which comprises a top wall and a peripheral wall which cooperate to define a breather chamber having an open bottom; 
 said breather apparatus further comprising a plurality of component pairs which project from an inside surface of the top wall in the breather chamber, each component pair comprising a fixing boss and a rib which is coextensive and integrally formed with its associated fixing boss; 
 wherein the cylinder head cover further comprises a breather plate fixed to the fixing bosses, the breather plate effectively covering the open bottom of the breather chamber, the breather chamber being partly partitioned by the ribs thereby defining a plurality of gas flow paths leading from a blowby gas inflow port to a blowby gas outflow port; 
 wherein each of the ribs extends obliquely from a respective side portion of the peripheral wall, relative to a direction in which blowby gas flows in through the inflow port, each of the ribs extending up to where it is continuous with one of the fixing bosses; and 
 wherein each of the ribs has a projecting lower edge portion which is partly cut out forming a concave portion. 
 
     
     
       2. The breather apparatus according to  claim 1 , wherein:
 the peripheral wall has an approximately rectangular cylindrical shape; 
 the inflow port is formed in each of a left and a right portion of one of a pair of opposing long side walls included in the peripheral wall; 
 the outflow port is formed in a part upwardly projecting from a first intermediate portion of the other of the pair of opposing long side walls, the first intermediate portion being closer to one end than to the other end of the other long side wall; 
 the ribs total three, the three ribs being formed extending from a left portion, a right portion, and a second intermediate portion, respectively, of the other long side wall, the second intermediate portion being closer to the other end than to the one end of the other long side wall; and 
 the two ribs extending from the left and right portions of the other long side wall extend obliquely such that they gradually approach each other as they approach the one of the pair of opposing long side walls, and the rib extending from the second intermediate portion extends in a same direction as a closer one of the two ribs. 
 
     
     
       3. The breather apparatus according to  claim 2 , wherein:
 the rib extending from the second intermediate portion of the other long side wall is partly in contact with the breather plate; and 
 the two ribs extending from the left and right portions of the other long side wall is not in contact with the breather plate. 
 
     
     
       4. The breather apparatus according to  claim 1 , wherein:
 the cylinder head cover is incliningly disposed with the side wall from which the ribs extend positioned higher than an opposite side wall; and 
 each of the ribs in contact with the breather plate that is inclined from horizontal has a cutout formed in an end portion thereof, the end portion being continuous with one of the fixing bosses. 
 
     
     
       5. The cylinder head cover of  claim 1 , further comprising at least one secondary air control device configured for placement above a camshaft. 
     
     
       6. The cylinder head cover of  claim 5 , wherein said secondary air control device comprises an upwardly projecting reed valve container, and a secondary air reed valve installed in said reed valve container. 
     
     
       7. The cylinder head cover of  claim 6 , wherein the cylinder head cover comprises two adjacently disposed reed valve containers on a first side thereof, and two adjacently disposed reed valve containers on another side thereof, with each of the reed valve containers having a rectangular open top. 
     
     
       8. The cylinder head cover of  claim 7 , further comprising two valve covers, wherein the open tops of each pair of adjacent reed valve containers are covered by a common one of said valve covers. 
     
     
       9. The cylinder head cover of  claim 8 , wherein the secondary air reed valve installed in each of the respective reed valve containers separates an upstream valve chamber covered by the valve cover, and a downstream valve chamber below said air reed valve. 
     
     
       10. An internal combustion engine, comprising:
 a cylinder head; 
 a cylinder head cover covering an upper portion of said cylinder head and having a breather apparatus formed therein, said breather apparatus comprising a part of the cylinder head cover which projects upwardly and which comprises a top wall and a peripheral wall which cooperate to define a breather chamber having an open bottom; 
 said breather apparatus further comprising a plurality of component pairs which project from an inside surface of the top wall in the breather chamber, each component pair comprising a fixing boss and a rib which is coextensive and integrally formed with its associated fixing boss; 
 wherein the cylinder head cover further comprises a breather plate fixed to the fixing bosses, the breather plate effectively covering the open bottom of the breather chamber, the breather chamber being partly partitioned by the ribs thereby defining a plurality of gas flow paths leading from a blowby gas inflow port to a blowby gas outflow port; 
 wherein each of the ribs extends obliquely from a respective side portion of the peripheral wall, relative to a direction in which blowby gas flows in through the inflow port, each of the ribs extending up to where it is continuous with one of the fixing bosses; and 
 wherein each of the ribs has a projecting lower edge portion which is partly cut out forming a concave portion. 
 
     
     
       11. The internal combustion engine of  claim 10 , wherein:
 the peripheral wall has an approximately rectangular cylindrical shape; 
 the inflow port is formed in each of a left and a right portion of one of a pair of opposing long side walls included in the peripheral wall; 
 the outflow port is formed in a part upwardly projecting from a first intermediate portion of the other of the pair of opposing long side walls, the first intermediate portion being closer to one end than to the other end of the other long side wall; 
 the ribs total three, the three ribs being formed extending from a left portion, a right portion, and a second intermediate portion, respectively, of the other long side wall, the second intermediate portion being closer to the other end than to the one end of the other long side wall; and 
 the two ribs extending from the left and right portions of the other long side wall extend obliquely such that they gradually approach each other as they approach the one of the pair of opposing long side walls, and the rib extending from the second intermediate portion extends in a same direction as a closer one of the two ribs. 
 
     
     
       12. The internal combustion engine of  claim 10 , wherein:
 the rib extending from the second intermediate portion of the other long side wall is partly in contact with the breather plate; and 
 the two ribs extending from the left and right portions of the other long side wall is not in contact with the breather plate. 
 
     
     
       13. The internal combustion engine of  claim 10 , wherein:
 the cylinder head cover is incliningly disposed with the side wall from which the ribs extend positioned higher than an opposite side wall; and 
 each of the ribs in contact with the breather plate that is inclined from horizontal has a cutout formed in an end portion thereof, the end portion being continuous with one of the fixing bosses. 
 
     
     
       14. The internal combustion engine of  claim 10 , further comprising a camshaft disposed below said cylinder head cover, and wherein said cylinder head cover further comprises at least one secondary air control device situated above the camshaft. 
     
     
       15. The internal combustion engine of  claim 14 , wherein said secondary air control device comprises an upwardly projecting reed valve container, and a secondary air reed valve installed in said reed valve container. 
     
     
       16. The internal combustion engine of  claim 14 , wherein said secondary air control device comprises two adjacently disposed reed valve containers on a first side thereof, and two adjacently disposed reed valve containers on another side thereof, with each of the reed valve containers having a rectangular open top. 
     
     
       17. The internal combustion engine of  claim 16 , further comprising two valve covers, wherein the open tops of each pair of adjacent reed valve containers are covered by a common one of said valve covers. 
     
     
       18. The internal combustion engine of  claim 17 , wherein the secondary air reed valve installed in each of the respective reed valve containers separates an upstream valve chamber covered by the valve cover, and a downstream valve chamber below said air reed valve. 
     
     
       19. The internal combustion engine of  claim 18 , further comprising an intake pipe attached to and projecting from the valve cover for introducing secondary air from an air cleaner into the upstream valve chamber. 
     
     
       20. The internal combustion engine of  claim 19 , wherein the cylinder head cover has a secondary air passage formed therein and extending downwardly from an opening in the downstream valve chamber.